U.S. patent number 9,101,348 [Application Number 14/209,239] was granted by the patent office on 2015-08-11 for surgical patient side cart with drive system and method of moving a patient side cart.
This patent grant is currently assigned to INTUITIVE SURGICAL OPERATIONS, INC.. The grantee listed for this patent is INTUITIVE SURGICAL OPERATIONS, INC.. Invention is credited to Paul G. Griffiths, Arjang M. Hourtash, Paul W. Mohr, David Robinson, Nitish Swarup, John Zabinski, Mark Zimmer.
United States Patent |
9,101,348 |
Griffiths , et al. |
August 11, 2015 |
Surgical patient side cart with drive system and method of moving a
patient side cart
Abstract
A patient side cart for a teleoperated surgical system can
include at least one manipulator arm portion for holding a surgical
instrument, a steering interface, and a drive system. The steering
interface may be configured to detect a force applied by a user to
the steering interface indicating a desired movement for the
teleoperated surgical system. The drive system can include at least
one driven wheel, a control module, and a model section. The
control module may receive as input a signal from the steering
interface corresponding to the force applied by the user to the
steering interface. The control module may be configured to output
a desired movement signal corresponding to the signal received from
the steering interface. The model section can include a model of
movement behavior of the patient side cart, the model section
outputting a movement command output to drive the driven wheel.
Inventors: |
Griffiths; Paul G. (Santa
Clara, CA), Hourtash; Arjang M. (Santa Clara, CA), Mohr;
Paul W. (Mountain View, CA), Robinson; David (Mountain
View, CA), Swarup; Nitish (Sunnyvale, CA), Zabinski;
John (Fremont, CA), Zimmer; Mark (Fremont, CA) |
Applicant: |
Name |
City |
State |
Country |
Type |
INTUITIVE SURGICAL OPERATIONS, INC. |
Sunnyvale |
CA |
US |
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Assignee: |
INTUITIVE SURGICAL OPERATIONS,
INC. (Sunnyvale, CA)
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Family
ID: |
51581029 |
Appl.
No.: |
14/209,239 |
Filed: |
March 13, 2014 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20140297130 A1 |
Oct 2, 2014 |
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Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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61791889 |
Mar 15, 2013 |
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61895249 |
Oct 24, 2013 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61B
50/13 (20160201); G05D 1/0011 (20130101); B25J
5/007 (20130101); A61B 50/10 (20160201); A61B
50/18 (20160201); A61B 2050/185 (20160201); A61B
34/30 (20160201) |
Current International
Class: |
B62D
6/00 (20060101); B25J 5/00 (20060101); A61B
19/02 (20060101); A61B 19/00 (20060101) |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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H05286453 |
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Nov 1993 |
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JP |
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2010008204 |
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Jan 2010 |
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JP |
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Other References
International Search Report and Written Opinion for Application No.
PCT/US14/26153, mailed on Aug. 14, 2014, 16 pages. cited by
applicant .
International Search Report and Written Opinion for Application No.
PCT/US14/26374, mailed on Jul. 24, 2014, 15 pages. cited by
applicant .
Vertut, Jean and Phillipe Coiffet, Robot Technology: Teleoperation
and Robotics Evolution and Development, English translation,
Prentice-Hall, Inc., Inglewood Cliffs, NJ, USA 1986, vol. 3A, 332
pages. cited by applicant.
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Primary Examiner: Edwards; Jerrah
Parent Case Text
This application claims the benefit of U.S. Provisional Application
No. 61/791,889, filed Mar. 15, 2013, and U.S. Provisional
Application No. 61/895,249, filed Oct. 24, 2013, each of which is
incorporated by reference herein in its entirety.
Claims
What is claimed is:
1. A patient side cart for a teleoperated surgical system,
comprising: at least one manipulator arm portion for holding a
surgical instrument; a steering interface configured to detect a
force applied by a user to the steering interface indicating a
desired movement for the teleoperated surgical system, and a drive
system, the drive system comprising: at least one driven wheel; a
control module for receiving as input a signal from the steering
interface corresponding to the force applied by the user to the
steering interface, the control module being configured to output a
desired movement signal corresponding to the signal received from
the steering interface; and a model section comprising a model of
movement behavior of the patient side cart, the model section
outputting a movement command output to drive the driven wheel.
2. The patient side cart of claim 1, wherein the model section is
configured to receive the desired movement signal as input.
3. The patient side cart of claim 2, the drive system further
comprising a feedback control module configured to receive an error
output corresponding to a difference between the movement command
output and an actual movement of the patient side cart, the
feedback control module being configured to output a feedback
command output to correct the movement command output on a basis of
the error output.
4. The patient side cart of claim 3, wherein the feedback control
module includes a fore/aft feedback control module and a yaw
feedback control module.
5. The patient side cart of claim 4, wherein the fore/aft feedback
control module is configured to receive a first error output
corresponding to a difference between the fore/aft movement command
output and the actual movement of the patient side cart, the
feedback control module being configured to output a fore/aft
feedback command output to correct the fore/aft movement command
output on a basis of the error output.
6. The patient side cart of claim 5, wherein the yaw feedback
control module is configured to receive a second error output
corresponding to a difference between the yaw command output and
the actual movement of the patient side cart, the feedback control
module being configured to output a yaw feedback command output to
correct the yaw movement command output on a basis of the error
output.
7. The patient side cart of claim 2, the drive system further
comprising: an error detector configured to compare the desired
movement signal with an output of the driven wheel and produce an
error output corresponding to a difference between the desired
movement signal and the output of the driven wheel; a feedback
control module configured to receive the error output and output a
feedback command output to correct the movement command output.
8. The patient side cart of claim 7, further comprising a sensor
configured to detect a rotational speed of the at least one driven
wheel to provide the output of the at least one driven wheel.
9. The patient side cart of claim 2, wherein the control module
includes a first control module configured to produce a desired
fore/aft movement signal corresponding to the signal received from
the steering interface and a second control module configured to
produce a desired yaw rate signal corresponding to the signal
received from the steering interface.
10. The patient side cart of claim 9, wherein the model section
includes a fore/aft model section configured to produce a fore/aft
command output based on the desired fore/aft movement signal, and a
yaw rate model section configured to produce a yaw rate command
output based on the desired yaw rate signal.
11. The patient side cart of claim 1, wherein the drive system
comprises a plurality of driven wheels configured to rotate at
differing speeds.
12. The patient side cart of claim 11, wherein the drive system is
configured to produce individual movement command outputs for each
of the driven wheels.
13. The patient side cart of claim 11, wherein the drive system is
configured to turn the patient side cart by commanding driven
wheels on opposite sides of the cart to turn at different
speeds.
14. The patient side cart of claim 12, wherein the manipulator
portion for holding the surgical instrument is located at a
relative front portion of the patient side cart and the steering
interface is located at a relative rear portion of the patient side
cart, the front and rear portions being relative to a user engaging
the steering interface to move the cart.
15. The patient side cart of claim 14, wherein the driven wheels
are located at the relative front portion of the patient side cart,
and wherein the cart further comprises at least one wheel that is
not driven and is located at the rear portion of the patient side
cart.
16. The patient side cart of claim 1, further comprising a kick
plate configured to cease power to the drive system when the kick
plate is activated by a user.
17. The patient side cart of claim 1, wherein the control module
limits a speed of the patient side cart on a basis of a
configuration of the patient side cart.
18. The patient side cart of claim 1, the steering interface
further comprising a dead man switch that provides a signal to the
drive system when the dead man switch is actuated, wherein the
drive system is configured to cease power to the at least one
driven wheel to stop movement of the cart when the dead man switch
is no longer actuated.
19. A method of moving a patient side cart of a teleoperated
surgical system, the patient side cart including a steering
interface and a surgical instrument, the method comprising the
steps of: detecting a force applied to the steering interface with
a sensor of the steering interface; transmitting an input
corresponding to the applied force from the steering interface
sensor to a drive system of the patient side cart; transmitting a
desired movement command output based on the input corresponding to
the applied force that is received from the steering interface; and
transmitting a movement command output based on the desired
movement signal and a modeled behavior of the patient side
cart.
20. The method of claim 19, further comprising the steps of:
comparing the movement command output to an actual movement of the
patient side cart; generating an error output based on the step of
comparing the movement command output to the actual movement of the
patient side cart.
21. The method of claim 19, further comprising a step of outputting
a feedback command output to correct the movement command output on
a basis of the error output.
22. The method of claim 21, wherein the step of transmitting the
movement command output includes transmitting a fore/aft feedback
command output and a yaw rate command output; and wherein the step
of outputting a feedback command output includes outputting a
fore/aft feedback command output to correct the fore/aft command
output and outputting a yaw rate feedback command output to correct
the yaw rate command output.
Description
TECHNICAL FIELD
Aspects of the present disclosure relate to a teleoperated
(robotic) surgical system patient side cart having a drive system
for a user to maneuver the cart and methods of moving a patient
side cart.
INTRODUCTION
The section headings used herein are for organizational purposes
only and are not to be construed as limiting the subject matter
described in any way.
Some minimally invasive surgical techniques are performed remotely
through the use of teleoperated (robotically-controlled) surgical
instruments. In teleoperated (robotically-controlled) surgical
systems, surgeons manipulate input devices at a surgeon console,
and those inputs are passed to a patient side cart that interfaces
with one or more teleoperated surgical instruments. Based on the
surgeon's inputs at the surgeon console, the one or more
teleoperated surgical instruments are actuated at the patient side
cart to operate on the patient, thereby creating a master-slave
control relationship between the surgeon console and the surgical
instrument(s) at the patient side cart.
A patient side cart need not remain stationary in a particular
location, such as within one operating room, but instead may be
moved from one location to another. For example, a patient side
cart may be moved from one location to another, such as from one
location in an operating room to another location in the same
operating room. In another example, a patient side cart may be
moved from one operating room to another operating room.
One consideration in moving a patient side cart of a teleoperated
surgical system is the ease with which the patient side cart may be
moved by a user. Due to its weight, size, and overall
configuration, it may be desirable to provide a patient side cart
that enables a user to move and maneuver the patient side cart with
relative ease. It may further be desirable to configure a patient
side cart that can be moved from one location to another in a safe
manner.
SUMMARY
Exemplary embodiments of the present disclosure may solve one or
more of the above-mentioned problems and/or may demonstrate one or
more of the above-mentioned desirable features. Other features
and/or advantages may become apparent from the description that
follows.
In accordance with at least one exemplary embodiment, a patient
side cart for a teleoperated system comprises at least one
manipulator arm portion for holding a surgical instrument, a
steering interface, and a drive system. The steering interface may
be configured to detect a force applied by a user to the steering
interface indicating a desired movement for the teleoperated
surgical system. The drive system may comprise at least one driven
wheel, a control module, and a model section. The control module
may receive as input a signal from the steering interface
corresponding to the force applied by the user to the steering
interface. The control module may be configured to output a desired
movement signal corresponding to the signal received from the
steering interface. The model section may comprise a model of
movement behavior of the patient side cart, the model section
outputting a movement command output to drive the driven wheel.
In accordance with at least one exemplary embodiment, a method of
moving a patient side cart of a teleoperated surgical system, the
patient side cart including a steering interface and a surgical
instrument comprises the steps of: detecting a force applied to the
steering interface with a sensor of the steering interface,
transmitting an input corresponding to the applied force from the
steering interface sensor to a drive system of the patient side
cart, transmitting a desired movement command output based on the
input corresponding to the applied force that is received from the
steering interface, and transmitting a movement command output
based on the desired movement signal and a modeled behavior of the
patient side cart.
Additional objects, features, and/or advantages will be set forth
in part in the description which follows, and in part will be
obvious from the description, or may be learned by practice of the
present disclosure and/or claims. At least some of these objects
and advantages may be realized and attained by the elements and
combinations particularly pointed out in the appended claims.
It is to be understood that both the foregoing general description
and the following detailed description are exemplary and
explanatory only and are not restrictive of the claims; rather the
claims should be entitled to their full breadth of scope, including
equivalents.
BRIEF DESCRIPTION OF THE DRAWINGS
The present disclosure can be understood from the following
detailed description, either alone or together with the
accompanying drawings. The drawings are included to provide a
further understanding of the present disclosure, and are
incorporated in and constitute a part of this specification. The
drawings illustrate one or more exemplary embodiments of the
present teachings and together with the description serve to
explain certain principles and operation. In the drawings,
FIG. 1 is a diagrammatic view of an exemplary teleoperated surgical
system in accordance with at least one exemplary embodiment;
FIG. 2 is a schematic perspective view of an exemplary embodiment
of a patient side cart that includes a steering interface;
FIG. 3 is a plan schematic view of an exemplary embodiment of a
wheel arrangement of a patient side cart with a steering
interface;
FIG. 4 is schematic top view of an exemplary embodiment of a
patient side cart in a stowed configuration;
FIG. 5 is a schematic block diagram of an exemplary embodiment of a
drive system for a patient side cart;
FIG. 6 is a schematic block diagram of an exemplary embodiment of a
control system of a drive system for a patient side cart;
FIG. 7 is a schematic block diagram of an exemplary embodiment of a
control system for a patient side cart that includes feedback
control;
FIG. 8 is a schematic block diagram of another exemplary embodiment
of a control system for a patient side cart that includes feedback
control; and
FIG. 9 is a plan schematic view of an exemplary embodiment of a
wheel arrangement of a patient side cart.
DETAILED DESCRIPTION
This description and the accompanying drawings that illustrate
exemplary embodiments should not be taken as limiting. Various
mechanical, compositional, structural, electrical, and operational
changes may be made without departing from the scope of this
description and the invention as claimed, including equivalents. In
some instances, well-known structures and techniques have not been
shown or described in detail so as not to obscure the disclosure.
Like numbers in two or more figures represent the same or similar
elements. Furthermore, elements and their associated features that
are described in detail with reference to one embodiment may,
whenever practical, be included in other embodiments in which they
are not specifically shown or described. For example, if an element
is described in detail with reference to one embodiment and is not
described with reference to a second embodiment, the element may
nevertheless be claimed as included in the second embodiment.
For the purposes of this specification and appended claims, unless
otherwise indicated, all numbers expressing quantities,
percentages, or proportions, and other numerical values used in the
specification and claims, are to be understood as being modified in
all instances by the term "about," to the extent they are not
already so modified. Accordingly, unless indicated to the contrary,
the numerical parameters set forth in the following specification
and attached claims are approximations that may vary depending upon
the desired properties sought to be obtained. At the very least,
and not as an attempt to limit the application of the doctrine of
equivalents to the scope of the claims, each numerical parameter
should at least be construed in light of the number of reported
significant digits and by applying ordinary rounding
techniques.
It is noted that, as used in this specification and the appended
claims, the singular forms "a," "an," and "the," and any singular
use of any word, include plural referents unless expressly and
unequivocally limited to one referent. As used herein, the term
"include" and its grammatical variants are intended to be
non-limiting, such that recitation of items in a list is not to the
exclusion of other like items that can be substituted or added to
the listed items.
Further, this description's terminology is not intended to limit
the invention. For example, spatially relative terms--such as
"beneath", "below", "lower", "above", "upper", "proximal",
"distal", and the like--may be used to describe one element's or
feature's relationship to another element or feature as illustrated
in the figures. These spatially relative terms are intended to
encompass different positions (i.e., locations) and orientations
(i.e., rotational placements) of a device in use or operation in
addition to the position and orientation shown in the figures. For
example, if a device in the figures is turned over, elements
described as "below" or "beneath" other elements or features would
then be "above" or "over" the other elements or features. Thus, the
exemplary term "below" can encompass both positions and
orientations of above and below. A device may be otherwise oriented
(rotated 90 degrees or at other orientations) and the spatially
relative descriptors used herein interpreted accordingly.
Various exemplary embodiments of the present disclosure contemplate
a cart with a drive system and methods of moving a cart. Such a
cart may be, for example, patient side cart of a teleoperated
surgical system that includes a drive system. The drive system may
include, for example, a control system that includes an inverse
model of cart behavior. Further, the control system may include
error correction, such as, for example, feedback control. The
features of the exemplary embodiments described herein may be
applied to other wheeled objects, such as, for example, imaging
equipment, operating tables, and other wheeled devices.
A patient side cart of a teleoperated surgical system need not
remain stationary in a particular location, such as within one
operating room, but instead may be moved from one location to
another. For example, a patient side cart may be moved from one
location to another, such as from one location in an operating room
to another location in the same operating room. In another example,
a patient side cart may be moved from one operating room to another
operating room.
Due to its size and the equipment and instrument that it may
include, a patient side cart may have a considerable mass. For
instance, a patient side cart may weigh from about 1000 pounds to
about 2000 pounds, for example. In another example, an exemplary
patient side cart may have a weight ranging from about 1200 pounds
to about 1850 pounds. Furthermore, a patient side cart may be large
in size. If a person were required to supply the force required to
move a patient side cart, it may be difficult for the person to
also steering the cart while providing the necessary motive force.
Therefore, due to its weight, size, and overall configuration, it
may be desirable to provide a patient side cart that enables a user
to move and maneuver the patient side cart with relative ease. It
may further be desirable to configure a patient side cart that can
be moved from one location to another in a safe manner.
One way to address these issues is to provide a patient side cart
with a system that provides a force to assist with moving the
patient side cart. Such a system may be a drive system that
includes one or more devices that drive or move a patient side cart
so that a user need not provide all of the force necessary to move
the cart. For instance, a drive system may provide all of the force
necessary to move a patient side cart or a drive system may provide
a large majority of the force necessary to move a patient side cart
so that a user may sense the weight and/or handling of the cart
when the user applies a force to move the cart.
A drive system for a patient side cart may interact with controls
that a user operates to move the cart. To control the speed at
which a patient side cart moves, the controls may include a
throttle to provide an input to a drive system of the cart. In such
a case, the controls may also include a brake to control stopping
of the patient side cart. The controls would also require a
steering device so that a user could indicate to the drive system
what direction a patient side cart should be driven in. However,
such an array of controls may be somewhat difficult for a user to
operate, particularly if the user is not familiar with the
controls. Therefore, it may be desirable to provide a patient side
cart with a drive system and controls that are relatively easy to
operate in a simple manner.
Various exemplary embodiments of the present disclosure contemplate
a patient side cart of a teleoperated surgical system in which the
patient side cart includes a steering interface for a user that
operates in concert with a drive control system. One consideration
in moving a patient side cart of a teleoperated surgical system is
the ease with which the patient side cart may be moved by a
user.
The steering interface may permit a user to move the patient side
cart in a relatively easy and familiar manner without the use of
multiple steering and drive interface devices. A steering interface
in accordance with various exemplary embodiments may include
"intelligence" in that they can enable the storage of various
calibration data that can be provided to a control processor that
uses drive control algorithms for motor-assisted driving of the
cart. Such data may be used for various purposes, such as to
calibrate devices of the steering interface which may vary to a
degree from one to another. For instance, data could include
calibration data for one or more sensors that are included in the
steering interface. Calibration of a component of a steering
interface, such as a force sensor, may include storing calibration
data in a data storage device of the steering interface. The
calibration may include, for instance, data that associates a force
detected by a force sensor with a signal that a drive system of a
cart may use to control movement of a cart. The calibration data
may associate the detected force with a signal for a drive system
through an algorithm, such as through one or more equations, look
up tables, or other functions.
The intelligence functions of the steering interface may be
configured to function automatically, such as when a steering
interface is initially mounted to a cart and connections are made
between the cart and steering interface to permit transmittal of
data to the cart. For instance, the calibration function of a
steering interface may function automatically when the steering
interface is mounted to a cart, causing stored data from a
calibration device of the steering interface to calibrate signals
transmitted from one or more force sensors to a drive system of the
cart.
In various exemplary embodiments, the steering interface may be
replaceable, e.g., in the field, such as when the steering
interface or component thereof is damaged or otherwise
non-functional. In addition, if one or more components of a
steering interface is damaged or otherwise requires repair, the
steering interface could be removed so the component may be
repaired or replaced. Recalibration could also be conducted on
components of a steering interface once the steering interface has
been removed so that the steering interface is ready to function
when the steering interface is attached to a cart. According to an
exemplary embodiment, a steering interfaces described herein may be
used with various carts, including carts of different sizes and/or
configurations. Further, various exemplary embodiments contemplate
a steering interface for a patient side cart of a teleoperated
surgical system.
Steering interfaces of the exemplary embodiments described herein
may be provided in various forms. According to one exemplary
embodiment, a steering interface for a patient side cart of a
teleoperated surgical system may be provided in the form of a
handlebar. However, the form or shape of the steering interface for
a user of a patient side cart of a teleoperated surgical system is
not limited to this exemplary embodiment. For example, a steering
interface for a patient side cart may be in the form of a plurality
of handlebars, one or more handles, a steering wheel, combinations
of these interfaces, and other shapes and forms used for steering
interfaces.
Teleoperated Surgical System
With reference to FIG. 1, a teleoperated surgical system 100 is
provided which, in an exemplary embodiment, performs minimally
invasive surgical procedures by interfacing with and controlling a
variety of remotely operated surgical instruments, such as one or
more surgical instruments 102, as those of ordinary skill in the
art are generally familiar. The surgical instruments 102 may be
selected from a variety of instruments that are configured to
perform various surgical procedures, and in accordance with various
exemplary embodiments can have a variety of configurations to
implement surgical procedures of conventional surgical instruments.
Non-limiting examples of the surgical instruments 102 include, are
but not limited to, instruments configured for suturing, stapling,
cutting, grasping, applying electrosurgical energy (e.g., cautery
energy), and a variety of other instruments with which those having
ordinary skill in the art are generally familiar.
As illustrated in the schematic view of FIG. 1, the teleoperated
surgical system 100 includes a patient side cart 110, a surgeon
console 120, and a control cart 130. In non-limiting exemplary
embodiments of the teleoperated surgical system, the control cart
130 includes "core" processing equipment, such as core processor
170, and/or other auxiliary processing equipment, which may be
incorporated into or physically supported at the control cart 130.
The control cart 130 may also include other controls for operating
the teleoperated surgical system. As will be discussed in more
detail below, in an exemplary embodiment, signal(s) or input(s)
transmitted from surgeon console 120 may be transmitted to one or
more processors at control cart 130, which may interpret the
input(s) and generate command(s) or output(s) to be transmitted to
the patient side cart 110 to cause manipulation of one or more of
surgical instruments 102 and/or patient side manipulators 140a-140d
to which the surgical instruments 102 are coupled at the patient
side cart 110. It is noted that the system components in FIG. 1 are
not shown in any particular positioning and can be arranged as
desired, with the patient side cart 110 being disposed relative to
the patient so as to affect surgery on the patient. A non-limiting,
exemplary embodiment of a teleoperated surgical system with which
the principles of the present disclosure may be utilized is a da
Vinci.RTM. Si (model no. IS3000) commercialized by Intuitive
Surgical, Inc. of Sunnyvale, Calif.
In general, the surgeon console 120 receives inputs from a user,
e.g., a surgeon, by various input devices, including but not
limited to, gripping mechanisms 122 and foot pedals 124, and serves
as a master controller by which the instruments 102 mounted at the
patient side cart 110 act as slaves to implement the desired
motions of the surgical instrument(s) 102, and accordingly perform
the desired surgical procedure. For example, while not being
limited thereto, the gripping mechanisms 122 may act as "master"
devices that may control the surgical instruments 102, which may
act as the corresponding "slave" devices at the manipulator arms
140, and in particular control an end effector and/or wrist of the
instrument as those having ordinary skill in the art are familiar
with. Further, while not being limited thereto, the foot pedals 124
may be depressed to provide, for example, monopolar or bipolar
electrosurgical energy, or to activate a variety of other functions
(e.g., suction, irrigation, etc.) at the instruments 102.
In various exemplary embodiments, suitable output units may
include, but are not limited to, a viewer or display 126 that
allows the surgeon to view a three-dimensional image of the
surgical site, for example, during the surgical procedure, e.g.,
via an optical endoscope 103 at the patient side cart 110. Other
output units may include a speaker (or other component capable of
transmitting sound), and/or a component with which a surgeon is in
contact that can vibrate or the like to provide haptic feedback. In
various exemplary embodiments, the one or more output units may be
part of the surgeon console 120 and signals can be transmitted from
the control cart 130 thereto. Although in various exemplary
embodiments, one or more input mechanisms 122, 124 may be
integrated into the surgeon console 120, various other input
mechanisms may be added separately and provided so as to be
accessible to the surgeon during use of the system, but not
necessarily integrated into the surgeon console 120. In the context
of the present disclosure, such additional input mechanisms are
considered part of the surgeon console.
Thus, a "surgeon console" as used herein includes a console that
comprises one or more input devices 122, 124 that a surgeon can
manipulate to transmit signals, generally through a control cart
such as 130 to actuate a remotely-controllable kinematic structure
(e.g., surgical instruments 102 mounted at arms 140) at the patient
side cart 110. The surgeon console 120 may also include one or more
output devices that can provide feedback to the surgeon. As used
herein, it should be understood, however, that a surgeon console
can include a unit (e.g., substantially as shown by element 120 in
FIG. 1) that integrates the various input and output devices, with,
for example, a display, but also can include separate input and/or
output devices that are in signal communication with the
controllers, such as controllers provided at the control cart and
accessible by a surgeon, although not necessarily integrated within
a unit with various other input devices. As an example, input units
may be provided directly at the control cart 130 and may provide
input signals to a processor at the control cart. As such, a
"surgeon console" does not necessarily require all of the input and
output devices to be integrated into a single unit and can include
one or more separate input and/or output devices.
The exemplary embodiment of FIG. 1 illustrates a patient side cart
110 with multiple, independently moveable manipulator arms 140 that
each support an actuation interface assembly 146 and are configured
to hold and manipulate various tools, including, but not limited
to, for example, a surgical instrument 102, and an endoscope
imaging device 103. However, those having ordinary skill in the art
will appreciate that other patient side cart configurations may be
used without departing from the scope of the present disclosure and
claims.
Based on the commands input to input devices at, for example, the
surgeon console 120, the patient side cart 110 can position and
actuate the instrument(s) 102 to perform a desired medical
procedure via the actuation interface assemblies 146 at the
manipulator arms 140. The actuation interface assemblies 146 are
configured to engage with transmission mechanisms 147 provided at a
proximal end of the surgical instruments 102 (the general
"proximal" and "distal" directions being shown in FIG. 1 relative
to the surgical instrument). The surgical instrument 102 and the
actuation interface assembly 146 may be mechanically and/or
electrically connected to be able to operate the instrument 102. A
patient side cart 110 may include a plurality of wheels 149 mounted
or otherwise attached to the cart 110, such as to a base 148 of the
cart 110.
The teleoperated surgical system 100 can include a control system
that receives and transmits various control signals to and from the
patient side cart 110 and the surgeon console 120. The control
system can transmit light and process images (e.g., from an
endoscope at the patient side cart 110) for display, such as, e.g.,
display 126 at the surgeon console 120 and/or on a display 132
associated with the control cart 130.
In exemplary embodiments, the control system may have all control
functions integrated in one or more processors, such as a core
processor 170 at the control cart 130, or additional controllers
(not shown) may be provided as separate units and/or supported
(e.g., in shelves) on the control cart 130 for convenience. The
latter may be useful, for example, when retrofitting existing
control carts to control surgical instruments requiring additional
functionality, for example, by providing electrical energy for use
in monopolar and bipolar applications.
One of ordinary skill in the art would recognize that the
controllers, e.g., core processor 170, provided at control cart 130
may be implemented as part of a control system, which, as will be
discussed in more detail below, controls various functions of the
present disclosure. One of ordinary skill in the art would
recognize that functions and features of the controllers, e.g.,
core processor 170, may be distributed over several devices or
software components, including, but not limited to, processors at
any of the surgeon console 120, patient side cart 110 and/or other
devices incorporating processors therein. Functions and features of
the control system, which may include core processor 170, may be
distributed across several processing devices.
Due to the size and overall configuration of a patient side cart,
including the jointed arms, possibly mounted with one or more
surgical instruments, moving a patient side cart may require a
significant exertion of effort and can be cumbersome for a user.
Further, it may be challenging to move a patient side cart in a way
in which it is relatively easy to control the movements and
steering of the patient side cart, due to the weight and size of
the patient side cart.
Turning to FIG. 2, an exemplary embodiment of a patient side cart
310 is shown schematically. A patient side cart 310 may be arranged
according to any of the exemplary embodiments described herein,
such as with reference to FIG. 1 described above. For example, a
patient side cart 310 may include one or more patient side
manipulator(s) 340, which can also have one or more surgical
instruments 302 installed thereat. A patient side cart 310 may
include wheels (not shown) on its base to permit movement of the
cart. For example, a patient side cart 310 may include three wheels
or four wheels. One or more of the wheels may be driven by a drive
system included in the patient side cart 310 that provides motive
force to the driven wheel(s), as will be discussed below.
According to an exemplary embodiment, a patient side cart may
include a steering interface that receives input from a user
indicating what direction the user would like the patient side cart
to move in. In addition, the steering interface may receive input
from a user indicating at what speed the user would like the
patient side cart, such as by detecting the amount of force a user
applies to the device.
According to an exemplary embodiment, a patient side cart 310 of a
teleoperated surgical system may include a steering interface 300,
as shown in FIG. 2. In one exemplary embodiment, a steering
interface 300 may be configured as described in U.S. application
Ser. No. 14/208,663, filed on Mar. 13, 2014 and claiming priority
to U.S. Provisional Application No. 61/791,924 entitled "Surgical
Patient Side Cart with Steering Interface" and filed on Mar. 15,
2013, each of which is hereby incorporated by reference in its
entirety. However, steering interfaces having other configurations
also can be employed in conjunction with the drive and control
systems according to exemplary embodiments of the present
disclosure. A steering interface 300 may be used to detect forces
applied by a user to the steering interface 300, which in turn may
issue a signal to a controller of a drive system of a patient side
cart 310, which causes the patient side cart 310 to be driven and
steered in a desired manner. As shown in the example of FIG. 2, a
steering interface 300 may be attached to a rear of a patient side
cart 310, with one or more manipulator arms 302 being located at a
front of the patient side cart 310. However, the exemplary
embodiments described herein are not limited to a patient side cart
310 with a steering interface 300 attached to a rear, and the
steering interface 300 may instead be mounted on other portions of
a patient side cart 310, such as a front or side of the patient
side cart 310.
Drive System
Information received at a steering interface may be used by a drive
system of a patient side cart to provide motive force to one or
more transportation mechanisms of the cart. According to an
exemplary embodiment, a patient side cart may include one or more
wheels as transportation mechanisms to move the cart in a desired
direction. One or more of the wheels may be driven according to
commands issued from the drive system of the patient side cart.
Turning to FIG. 3, a top schematic view of an exemplary embodiment
of a wheel arrangement for a patient side cart 400 is shown. A
patient side cart 400 may include one or more front wheels 410, 412
and one or more rear wheels 420, as shown in FIG. 3. The front of a
patient side cart 400 may be, for example, where manipulator arms
are positioned. Thus, wheel 410 may be a front left wheel 410 while
wheel 412 may be a front right wheel 412.
According to an exemplary embodiment, one or more wheels of a
patient side cart 400 may be driven. In one exemplary embodiment,
the front wheels 410, 412 of a patient side cart 400 of FIG. 3 may
be driven while rear wheels 420 are not driven. According to an
exemplary embodiment, driven wheels may be individually driven by
separate motors. For instance, motors 411, 413 may be provided to
respectively drive wheels 410, 412. Further, motors 411, 413 may
drive wheels 410, 412 independently. In other examples, wheels in
the rear of a patient side cart may be driven or all wheels of a
patient side cart may be driven. Wheels that are driven may be
fixed so that the wheels are prevented from turning. According to
another embodiment, driven wheels may be permitted to turn, either
freely or in a controlled manner.
Wheels of a cart may be driven to produce a speed of, for example,
approximately 1 meter per second when the manipulator arms of the
cart are in a stowed, retracted position. Turning to FIG. 4, an
exemplary embodiment of a patient side cart 400 is shown in a
stowed configuration. A patient side cart 400 may include a
steering interface 430 and a plurality of manipulator arms 402
holding surgical instruments (not shown), such as according to the
embodiments of FIG. 1. In the stowed configuration shown in the
example of FIG. 4, the manipulator arms 402, and any respective
instruments and other components installed thereon, may be folded
into a relatively compact arrangement toward a center of the
patient side cart 400. Further, a post 404 upon which the
manipulator arms 402 may be mounted may be in a non-extended,
compact configuration as well. Those having ordinary skill in the
art would be familiar with various exemplary embodiments of patient
side carts having in which, for example, a central support post
from which one or more of the passively jointed manipulator arms
extend is provided in a telescoping arrangement so as to be raised
and lowered relative to the base of the cart. In a stowed
configuration, therefore, the post can be in the lowered,
non-extended position and the manipulator arms can be positioned
toward each other and proximate to a center portion of the
cart.
According to an exemplary embodiment, a wheel that is not driven
may be permitted to spin freely as the patient side cart is driven
and the wheel contacts a ground surface. For instance, rear wheels
420 of a patient side cart 400 may be permitted to turn in
direction A indicated in FIG. 3. According to an exemplary
embodiment, one or more wheels may have a configuration similar to
a caster wheel and may be permitted to turn freely about a vertical
axis so that a wheel may turn in a left and right direction as a
patient side cart changes direction. For instance, rear wheels 420
in FIG. 3 may have a configuration similar to a caster wheel and be
permitted to turn freely about a vertical axis. Such wheels may
also spin freely so that when a patient side cart is driven, freely
spinning wheels in contact with a ground surface also move. Wheels
may also be turned by steering mechanisms, such as linkages and/or
motors, according to steering input provided by a user.
Thus, according to one exemplary embodiment, a patient side cart
400 may include front wheels 410, 412 that are driven and rear
wheels 420 that are not driven but are permitted to freely turn, as
shown in FIG. 3. In other words, the wheels of a patient side cart
400 may have a configuration and arrangement opposite to those of a
shopping cart commonly used in grocery stores and other retailers
wherein the rear wheels (e.g., disposed proximate to the handle of
the shopping cart) are driven and the front wheels are castered. A
patient side cart 400 with a configuration such as in the exemplary
embodiment of FIG. 3 can minimize or avoid relatively large
sweeping motions, in particular at the front of the cart opposite
to where the steering interface is positioned. Minimizing such
large sweeping motions at the front of the cart provides the user
with greater control in maneuvering the cart and minimizes the risk
of collisions with the cart at the front of the cart where
visibility by a user may be limited as a user maneuvers the cart
from the rear end of the cart proximate the rear wheels 420.
As discussed above, when desiring to move the patient side cart
400, a user may engage a steering interface 430 of a patient side
cart 400 and impart a force to the steering interface 430 to
indicate which directions the user desires the patient side cart
400 to move in. For example, a user may push the steering interface
430 in the fore direction (relative to the front wheels 410, 412
and the rear wheels 420) along direction X in FIG. 3 or may pull
the steering interface 430 backwards in the aft direction along
direction X in FIG. 3 to indicate a desire to move a patient side
cart 400 either forward or backward.
In addition, a user may apply a force having at least a component
in the Y direction of FIG. 3 to indicate a desire to a turn the
patient side cart either to the left or right (relative to the
front wheels 410, 412 and the rear wheels 420 of the patient side
cart 400). Forces applied in the Y direction indicating a desire to
turn a patient side cart 400 may be used to provide a yaw control
of the patient side cart 400 and control turning of the cart 400.
For instance, a user may apply a lateral force to a steering
interface 430 along directions substantially perpendicular to the
forward and rearward directions of FIG. 3, which may substantially
correspond to a direction along a Y direction or axis. The sensor
configuration discussed above for detection of a force applied by a
user to indicate a desired movement for a patient side cart is one
exemplary way of sensing turning (e.g., yaw) and fore/aft steering
control, but other techniques also could be employed and sensor
configurations modified accordingly. For instance, according to
another exemplary embodiment, a user may indicate that the patient
side cart should turn by applying more force to one of a left
portion and right portion of the steering interface 430, in
relation to a left-right direction extending along the Y axis in
FIG. 3, than the other of the left portion and the right portion.
The steering interface 430 may be configured to detect the applied
forces and issue a signal to the control system of the drive
system, which commands the drive system to turn in the direction
desired by the user.
A patient side cart may include a drive system configured to
receive signal(s) from a steering interface (e.g., from one or more
sensors at the steering interface). A patient side cart may include
a control system or controller, which may be part of the drive
system or a separate device or system in communication with the
drive system. Referring again to FIG. 3, for example, the control
system may be configured to receive signal(s) or input(s) from a
steering interface 430 of a patient side cart 400 and, based upon
the received input(s), issue one or more command outputs or outputs
to control the driven wheel(s) of the patient side cart 400, such
as the driven front wheels 410, 412 shown in FIG. 3. For example, a
command output issued by the control system for the drive system of
a patient side cart may be a command output to drive a wheel to
move the cart in a forward or backward direction, and/or a command
output to drive a wheel in a way to provide a yaw rate and turn the
cart in a direction desired by a user.
Turning to FIG. 5, a schematic block diagram of one exemplary
embodiment of a drive system 500 for a patient side cart is shown
in communication with a steering interface 510. A steering
interface 510 may be configured as a handlebar according to the
embodiments described above for the steering interface 430 of FIG.
3, for example. For an exemplary steering interface that can be
used in conjunction with the Reference is made to U.S. application
Ser. No. 14/208,663, filed on Mar. 13, 2014 and claiming priority
to U.S. Provisional Application No. 61/791,924 entitled "Surgical
Patient Side Cart with Steering Interface" and filed on Mar. 15,
2013, each being incorporated by reference herein in its entirety.
The steering interface 510 may include one or more sensors to
detect forces applied by a user to indicate a desired movement for
a patient side cart. That is, as described above, the steering
interface can include one or more sensors for sensing push/pull and
turning forces indicating a desire to move the cart in the fore/aft
and left/right directions.
In the exemplary embodiment illustrated in FIG. 5, the steering
interface 510 includes a first sensor 512 and a second sensor 514
that detect forces along the X and Y directions (as shown in FIGS.
3 and 5). In various exemplary embodiments, the sensors 512 and 514
can be load cells. In an exemplary embodiment, the sensors 512 and
514 can be configured as those disclosed for use in the steering
interface described in U.S. application Ser. No. 14/208,663, filed
on Mar. 13, 2014 and claiming priority to U.S. Provisional
Application No. 61/791,924 entitled "Surgical Patient Side Cart
with Steering Interface" and filed on Mar. 15, 2013, each of which
is incorporated by reference herein in its entirety.
The steering interface 510 may issue or transmit a first input or
signal 516 from the first sensor 512 and a second input or signal
518 from the second sensor 514, which are received by the drive
system 500 of a patient side cart that the steering interface 510
is attached to. First input 516 and second input 518 may include
information about forces applied by the user to the steering
interface 510 to indicate a desired movement. For instance, first
input 516 and second input 518 may each include data corresponding
to a force detected in the X direction of FIG. 5 data, such as
F.sub.x data that will be discussed below, and data corresponding
to a force detected in the Y direction of FIG. 5, such as F.sub.y
data that will be discussed below.
Although first input 516 and second input 518 may be provided
separately, as shown in FIG. 5, first input 516 and second input
518 may be combined or otherwise provided as a single input.
Furthermore, although each of first input 516 and second input 518
may include both data for forces directed in the X direction and Y
direction of FIG. 5, such as F.sub.x data and F.sub.y data, first
input 516 and second input 518 may instead be processed so that one
input includes only F.sub.x data and the other input includes only
F.sub.y data when more than one input is provided.
According to an exemplary embodiment, a steering interface 510 may
include a plurality of sensors, such as the first sensor 512 and
the second sensor 514 shown in FIG. 5, so that information from the
sensors may be combined or compared to determine a desired motion
indicated by a user. For instance, F.sub.y data from the first
sensor 512 and from the second sensor 514 may be analyzed by the
drive system 500 to determine if a user is applying a force to the
steering interface 510 along the Y direction to indicate a desire
to turn a patient side cart. When the F.sub.y data indicates a
user's desire to turn a patient side cart, a command output may be
issued to cause the patient side cart to turn. F.sub.x data from
the first sensor 512 and from the second sensor 514 may be
similarly analyzed by the drive system 500 to determine a user's
desire to move a patient side cart in a fore/aft direction, such as
along the X direction.
According to an exemplary embodiment, a patient side cart may
include one or more devices to condition signals received from a
steering interface so that the signals may be further processed. As
shown in FIG. 5, a drive system 500 may include a signal
conditioner 520, which may include one or more devices with which
those of ordinary skill in the art have familiarity. For instance,
signal conditioner 520 may include an amplifier to increase the
power of signals 516, 518. Signal conditioner 520 also may include
an analog-to-digital converter to convert analog signals 516, 518
to a digital form for further processing. Signal conditioner 520
may include these devices in combination with one another. Once
signals 516, 518 have been conditioned by signal conditioner 520,
the signals may be sent via a high speed communication connection
522 to other components of the drive system 500. In a non-limiting
example, the high speed communication connection 522 may be an
RS422 type of connection.
Drive system 500 may further include a control system or controller
540, according to an exemplary embodiment. Control system 540 may
be configured to receive signal(s) (which may be first conditioned
and processed by signal conditioner 520) from a steering interface
510 indicating a desired movement for a patient side cart, to
analyze the received signals, and to issue one or more command
outputs to cause the patient side cart to move in the desired
manner.
According to an exemplary embodiment, control system 540 may issue
a separate command output for each driven wheel to effect a desired
movement for a patient side cart. For instance, if a patient side
cart has a first driven wheel 560 and a second driven wheel 562,
control system 540 may issue or transmit a command output 542 for
first driven wheel 560 and a command output 544 for second driven
wheel 562. First driven wheel 560 may be, for example, a front left
wheel, such as the front left wheel 410 of the patient side cart
400 of FIG. 3, while second driven wheel 562 may be, for example, a
front right wheel, such as the front right wheel 412 of the patient
side cart 400 of FIG. 3.
According to an exemplary embodiment, drive system 500 may include
one or more devices to cause a desired movement of driven wheels
560, 562. For example, drive system 500 may include one or more
devices 550, 552 that cause wheels 560, 562 to move according to
command outputs 542, 544 issued from the control system 540.
According to various exemplary embodiments, drive devices 550, 552
can be motors, although other types of devices familiar with those
of ordinary skill in the art to cause wheel motion according to a
command output also can be utilized. According to an exemplary
embodiment, each driven wheel may be provided with its own drive
device so that each driven wheel is independently driven. As shown
in FIG. 5, first driven wheel 560 may be driven by a first drive
device 550 and second driven wheel 562 may be driven by a second
drive device 562.
A drive system for a patient side cart may include sensors and
controls to sense a movement of the cart, compare that movement
with a movement desired by a user, and adjust the movement of the
cart accordingly. According to an exemplary embodiment, a drive
system 500 can be configured to detect movement of a patient side
cart and provide the detected movement to the drive system 500 for
possible correction. The detected movement may be used, for
instance, in a feedback type of control. Movement of the cart may
be detected indirectly, such as by detecting information from
various components that affect movement of the cart. For example,
as shown in FIG. 5, a first sensor 570 may be used to detect the
movement of the drive device 550 that drives driven wheel 560 and a
second sensor 572 may be used to detect the movement of the drive
device 552 that drives driven wheel 562.
Signals from sensors 570, 572 may be sent to control system 540 and
analyzed to determine the speeds of driven wheels 560, 562. The
control system 540 can calculate a turning rate of a patient side
cart, which can be determined on the basis of a difference in speed
between the first driven wheel 560 and the second driven wheel 562.
According to an exemplary embodiment, the information detected by
sensors 570, 572 may be used by control system 540 in a feedback
arrangement. However, the embodiments described herein are not
limited to a feedback control scheme but instead may use other
control schemes such as, for example, a feed forward control scheme
may be used in one or more control blocks of the overall scheme.
According to another exemplary embodiment, a drive system 500 may
include other types of sensors to determine the movement of a
patient side cart, such as an accelerometer and/or sensors that
detect other components of the cart, such as a wheel or axle
rotational speed. Further, the drive system 500 may be configured
to minimize or eliminate deadbands so the drive system 500 is
responsive, with little to no delay between the force applied by a
user to a steering interface and a desired movement of a patient
side cart. For instance, the components of a drive system 500
and/or steering interface 510 may be include high quality,
responsive components or may be otherwise configured to minimize
any delay in their responsiveness.
According to an exemplary embodiment, control system 540 may limit
the speed of a patient side cart on a basis of the configuration of
the cart. Control system 540 may analyze one or more signals
indicating a desired movement of a patient side cart and issue one
or more command outputs 542, 455 to driven wheels 560, 562 on a
basis of the configuration of the cart. For instance, if a patient
side cart is in stowed configuration, such as in the exemplary
embodiment of FIG. 4, control system 540 may permit a patient side
cart to travel at a speed and/or acceleration desired by a user or
limit the desired speed and/or acceleration by a small degree.
Conversely, if the patient side cart is not in a stowed
configuration, such as when manipulator arms are extended, control
system 540 may limit a desired speed and/or acceleration by a
greater amount than when the cart is in the stowed configuration.
The limitation on speed and/or acceleration may be imposed to
minimize instability during travel of a cart. According to an
exemplary embodiment, a first maximum speed and/or acceleration may
be imposed by control system 540 when a patient side cart is in a
stowed configuration and a second maximum speed and/or acceleration
may be imposed when the cart is in a non-stowed configuration, with
first maximum speed and/or acceleration being greater than the
second maximum speed and/or acceleration. However, the exemplary
embodiments are not limited to two maximum speeds and/or
accelerations but instead may provide various maximums, such as
varying the maximum speed and/or acceleration on a basis of the
configuration of a cart, such as an extent to which the components
of the cart, such as manipulator arms, are extended. Thus, control
system 540 may control and limit a desired speed and/or
acceleration for a patient side cart so that the cart travels at
lower speeds and/or accelerations when the cart is in non-stowed
configurations with extended manipulator arms than when the cart is
in a stowed configuration with retracted manipulator arms.
According to an exemplary embodiment, a patient side cart may
include one or more sensors to determine the configuration of a
patient side cart. For instance, one or more sensors may detect the
position of manipulator arms and provide signal(s) to control
system 540 about the manipulator arm positions. Position sensor(s)
may be, for example, proximity sensors, encoders connected to
components of a patient side cart, such as manipulator arm motors,
and other position sensors used by one of ordinary skill in the
art. Control system 540 may use the signal(s) to determine what
degree, if any, to limit a speed and/or acceleration of a patient
side cart. Other methods may be used to determine the position of
components of a patient side cart. For instance, commands sent to
drive motors of cart components, such as the drives for manipulator
arms, may be used to predict the location of the components, input
from a user providing information on the configuration of a cart
may be used to determine a state of the cart, and other location
determining methods used in the art may be utilized. Further, the
positions other components besides manipulator arms may be detected
when determining the configuration of a cart and to what degree a
desired speed and/or acceleration should be limited.
Turning to FIG. 6, a schematic block diagram for an exemplary
embodiment of a control system 600 for a drive system of a patient
side cart is shown. Control system 600 may be used, for example, as
the control system 540 shown in FIG. 5. Control system 600 may
receive one or more inputs or signals from a steering interface,
such as the steering interface 510 of FIG. 5. For instance, if a
steering interface 510 includes one or more sensors to measure
forces applied by a user in the X and Y directions of FIG. 5, the
sensors may detect the forces and issue signals corresponding to
the forces. These signal(s) or input(s) may be received by a
control system 600, which in turn may output command outputs to
drive wheels driven by the drive system.
For instance, a control system 600 may receive a signal or input
F.sub.x, which may correspond to the force applied to the steering
interface 510 in the X direction of FIG. 5. Control system 600 may
also receive a signal or input F.sub.y, which may correspond to the
force applied to the steering interface 510 in the Y direction of
FIG. 5. For example, in the exemplary embodiment wherein steering
interface 510 includes a plurality of sensors 512, 514, as shown in
FIG. 5, input F.sub.x and input F.sub.y may represent inputs or
signals from the plurality of sensors to indicate movements along
the X direction and the Y direction, respectively, that are desired
by a user of a patient side cart. As shown the exemplary embodiment
of FIG. 5, input F.sub.x and input F.sub.y may be provided
separately. In another embodiment, input F.sub.x and input F.sub.y
may be provided as a single input or signal. Further, each of input
F.sub.x and input F.sub.y may be provided as combined inputs from a
plurality of sensors of a steering interface (such that input
F.sub.x includes data from multiple sensors and input F.sub.y
includes data from multiple sensors), or separate F.sub.x and
F.sub.y inputs may be provided from each sensor of a steering
interface.
A control system may include one or more control modules configured
to receive an input signal, such as a signal from a steering
interface, and output a desired behavior. The desired behavior may
be, for example, a desired overall movement for the patient side
cart and/or may be desired individual movements for the driven
wheels of a patient side cart. For instance, a signal corresponding
to a force applied to a steering interface by a user can be
analyzed and an output of a desired movement may be provided. The
desired movement of the cart may correspond to the force applied to
the steering interface. An output of a desired movement may
represent, for instance, a desired velocity and/or acceleration for
a patient side cart. The input signal may be first conditioned
and/or processed, such as by signal conditioner 520 of FIG. 5,
before being converted to a desired behavior by a control module.
The desired behavior may be, for example, one or more of a desired
velocity, acceleration, and yaw (turning) rate.
According to an exemplary embodiment, a control system 600 may
include a first control module 610 and a second control module 612,
as shown in FIG. 6. First control module 610 may be configured to
receive signal F.sub.x, which may correspond to the force applied
to the steering interface 510 in the X direction of FIG. 5, analyze
signal F.sub.x, and output a desired fore/aft movement signal 602
along the X direction. Second control module 612 may be configured
to receive signal F.sub.y, which may correspond to the force
applied to the steering interface 510 in the Y direction of FIG. 5,
analyze signal F.sub.y, and output a desired yaw rate signal 622
for a patient side cart to effect turning of the cart. The desired
fore/aft movement signal 620 and the desired yaw rate signal 622
may correspond to a desired velocity and/or acceleration along the
X and Y directions, respectively.
To perform the actions of analyzing input signals F.sub.x, F.sub.y
and generating desired movement signals, control modules 610, 612
may include information that correlates forces applied to a
steering interface along the X and Y directions to desired
movements of the patient side cart in the X and Y directions. For
example, control modules 610, 612 may include maps, algorithms,
look-up tables, or other functions used in the art to correspond a
force input to a steering interface to a desired movement of a
patient side cart, such as a desired velocity and/or desired
acceleration. According to an exemplary embodiment, control modules
610, 612 may include one or more damping parameters to affect the
output of control modules 610, 612 in a desired manner, such as to
control the variation of the output of control modules 610, 612
over time.
Once a signal corresponding to a desired movement, such as a
desired velocity and/or desired acceleration, has been provided, a
command output that corresponds to the desired movement can be
output. For example, components of a drive system, such as a motor
driving a driven wheel, may not be configured to receive a desired
movement signal that is in form of a desired velocity and/or
desired acceleration and cause the desired movement of the cart
without the desired movement signal being in the form of a force or
a torque. In other words, a motor driving a driven wheel might be
configured to receive a command signal that is in the form of a
force (or a torque, which could be interpreted by static scaling,
for example) instead of in the form of a velocity and/or an
acceleration, which the motor might not be capable of interpreting.
Thus, desired movement signals represent an action or output that a
component, such as a motor for a driven wheel, should perform as
opposed to instructions or command outputs input to the motor to
cause the desired movement. To achieve the desired movement, a
control system may include one or more model sections configured to
produce command outputs, such as, for example, command outputs
corresponding to a force or torque, that are based on signals
corresponding to a desired movement. The command outputs (e.g., in
the form of a force or a torque) may be issued to components of a
drive system that cause movement, such as a motor for a driven
wheel.
Turning to FIG. 6, control system 600 may include a fore/aft model
section or module 630 configured to receive a desired raw fore/aft
movement signal or input 620, analyze the signal, and issue or
transmit a fore/aft command output 640 corresponding to the desired
movement. Fore/aft command output 640 may be, for example, a
command output to a motor to drive a driven wheel in a way that
will produce the desired fore/aft movement. For instance, fore/aft
command output 640 may be in the form of a force or a torque
command for a motor that drives a driven wheel. Control system 600
may also include a yaw model section or module 632 configured to
receive a desired raw yaw signal or input 622, analyze the signal,
and issue or transmit a yaw rate command output 642 corresponding
to the desired yaw rate for turning a patient side cart. Yaw rate
command output 642 may be in the form of a differential velocity
between driven wheels or a torque command for motors that drive
driven wheels. Thus, yaw rate command output 642 may be, for
example, a command output to motors of a drive system to produce a
torque that will cause a patient side cart to turn in a desired
manner. For example, if a drive system 500 includes a first driven
wheel 560 and a second driven wheel 562, yaw rate command output
642 may cause the driven wheels 560, 562 to rotate at different
speeds to produce an overall torque for a patient side cart that
will cause the cart to turn.
According to an exemplary embodiment, model sections 630, 632 can
be separate sections or modules of a control system 600, as shown
in FIG. 6, or may be a single section or module (not shown).
First command output 640 and second command output 642 may be
further processed to provide particular command outputs for
individual driven wheels. For example, if a patient side cart has a
first driven wheel 560 and a second driven wheel 562, as shown in
FIG. 5, first command output 640 and second command output 642 may
be further processed by control system 600 to provide separate
command outputs 542, 544 for first driven wheel 560 and second
drive wheel 562, as shown in FIG. 5. Command outputs 542, 544 may
be the same or may differ, depending upon the desired movement for
a patient side cart and the command outputs for driven wheels 560,
562 that effect the desired movement.
To convert a desired movement of a patient side cart, such as a
desired velocity and/or acceleration, into command outputs for
operation of the drive system, such as a force or a torque command
for a motor, model sections 630, 632 of a control system 600 may
include models configured to receive an incoming signal, such as
the desired fore/aft signal 620 and the desired yaw rate signal
622, and issue a command output to cause a patient side cart to
move in a desired manner. According to an exemplary embodiment, a
model may correlate a desired movement to a command output for
causing the desired movement, for example, by accounting for the
kinematics of a patient side cart, such as the mass and
configuration of cart. A map, algorithm, functional equation,
look-up table, or other technique with which those of ordinary
skill in the art would understand can be used to convert a signal
indicative of a desired motion, such as a desired velocity and/or
acceleration, into a command output, such as a force or torque, for
producing the desired motion.
In various exemplary embodiments, an inverse model can be used for
model sections 630, 632. An inverse model may be implemented by
receiving a desired behavior, such as, for example, a desired
motion of the patient side cart, as an input and outputting a
command to achieve the behavior. In other words, rather than
modeling a cart's behavior by receiving a command, such as a force
or torque, as an input and outputting a predicted behavior for the
cart, such as a velocity and/or acceleration, an inverse model does
the reverse.
According to an exemplary embodiment, fore/aft model section 630
can include an inverse model configured to receive a desired
fore/aft movement signal 620, which may correspond to a desired
velocity and/or acceleration, and output a fore/aft command output
640, which may represent a force or a torque, based on the modeled
fore/aft behavior for a patient side cart. The output fore/aft
command output 640 may then be received by, for example, a motor,
which interprets the output/fore aft command output 640 signal and
drives a driven wheel on the basis of the command output 640.
Similarly, yaw model section 632 can include an inverse model
configured to receive a desired yaw rate signal 622, which may
correspond to a desired velocity and/or acceleration, and output a
yaw rate command output 642, which may represent a force or a
torque, based on the modeled fore/aft behavior for a patient side
cart. The output yaw rate command output 642 may then be received
by, for example, one or more motors, which interpret the yaw rate
aft command output 642 signal and drive one or more driven wheels
on the basis of the command output 640 to turn a patient side
cart.
To provide a drive system that is relatively accurate and stable,
in various exemplary embodiments, a control system may include a
feedback control that measures the motion of a patient side cart
and feeds information about the motion of the cart back into the
control system. Turning to FIG. 7, an exemplary embodiment of a
control system including feedback control is shown. The control
system of FIG. 7 may, for example, be used as the control system
540 of FIG. 5. As shown in FIG. 7, an input signal 652 may be
provided to a control module 660 of the control system that
produces a desired movement signal 662. Input signal 652 may
correspond to signals F.sub.x, F.sub.y of FIG. 6, control module
660 may correspond to control modules 610, 612 of FIG. 6, and
desired movement signal 662 may correspond to desired movement
signals 620, 622 of FIG. 6. According to an exemplary embodiment,
control module 660 and a model section 670 may be arranged in a
feed forward arrangement, with desired movement signal 662 fed to
model section 670. The desired movement signal 662 is received by
model section 670, which produces a command output 672 that is sent
to a driven component 680 of a patient side cart to cause the
desired movement. A driven component 680 may be a driven wheel of a
patient side cart, such as one of front wheels 410, 412 shown in
FIG. 3. Model section 670 may correspond to model sections 630, 632
of FIG. 6 and command output 672 may correspond to command outputs
640, 642 of FIG. 6.
The feedback portion of a control system can measure the output 682
of the driven component 680, such as a velocity, acceleration,
and/or yaw rate. For example, a sensor may be configured to detect
the velocity, acceleration, and/or yaw rate of one or more driven
wheels or of the cart as a whole. For instance, a sensor may be
configured to detect a driven wheel rotational velocity (or the
angle, which can be used to derive the rotational velocity). The
output 682 may then be fed back and compared to a desired movement
signal 662 produced by the control module 660, such as at an error
detector 664.
If the error detector 664 determines that the output 682 and the
desired movement signal 662 differ, an error signal or output 666
is provided that is indicative that the patient side cart is not
moving as desired. The error output 666 is input to a feedback
control module 690. The error output 666 may represent a difference
between the output 682 and the desired movement signal 662. The
feedback control module 690 may generate a feedback command output
692 that is combined with the command output 672, such as at an
adder 674. Feedback command output 692 and command output 672 may
be combined to produce a corrected command output 694 that is
provided to the driven component 680 to provide a more accurate and
stable control of the movement of a patient side cart.
According to an exemplary embodiment, a patient side cart may
include feedback control for each of fore/aft movement and yaw rate
control. As discussed above, providing feedback control may provide
more accurate and stable controls for a patient side cart. These
advantages may be provided for each of the fore/aft and yaw
components of a patient side cart's movements.
Referring now to FIG. 8, a schematic block diagram is shown for an
exemplary embodiment of a control system 700 for a patient side
cart that includes feedback control for fore/aft movement and yaw
rate control. As shown in FIG. 8, the control system 700 receives
one or more input signals, such as F.sub.x, F.sub.y, as discussed
above in reference to FIG. 6. A first control module 710, which may
correspond to control module 610 of FIG. 6, may receive input
signal F.sub.x and output a desired fore/aft movement signal 712. A
fore/aft model section 730, which may correspond to fore/aft model
section 630 of FIG. 6, may receive the desired fore/aft movement
signal 712 and output a fore/aft command output 732. Similarly, a
second control module 720, which may correspond to control module
612 of FIG. 6, may receive input signal F.sub.y and output a
desired yaw rate signal 722 to a yaw rate model section 740, which
may correspond to yaw model 632 of FIG. 6, which issues a yaw rate
command output 742.
To provide specific command outputs to individual driven wheels of
a patient side cart, control system 700 may include a cart dynamics
section 780 configured to receive fore/aft command output 732 and
yaw rate command output 742 and issue command outputs for
individual wheels that will cause a patient side cart to move in
the fore/aft direction and turn at the desired yaw rate. For
instance, cart dynamics section 780 may analyze the fore/aft
command output 732 and the yaw rate command output 742 and issue a
left driven wheel torque command output 796 and a right driven
wheel torque command output 798. According to an exemplary
embodiment, command outputs may be provided to motors that driven
the driven wheels of a patient side cart. According to an
embodiment, left driven wheel torque command output 796 may be
issued for a left front wheel of a patient side cart, such as to
the motor for the left front wheel 410 of FIG. 4, and right driven
wheel torque command output 798 may be issued for a right front
wheel of a cart, such as to the motor for the right front wheel 412
of FIG. 3.
Left driven wheel torque command output 796 and a right driven
wheel torque command output 798 may be the same or may differ. For
instance, if the force applied by a user to a steering interface
indicates a desire to move a patient side cart forwards or
backwards along a straight line, such as along the X direction of
FIG. 3, the left driven wheel torque command output 796 and a right
driven wheel torque command output 798 may be the same to cause a
left front wheel and a right front to have the same torque and
rotate at the same rate.
However, if the force applied by a user to a steering interface
indicates a desire to turn a patient side cart, such as in a
direction having a Y direction component as shown in FIG. 3, the
left driven wheel torque command output 796 and a right driven
wheel torque command output 798 may differ so that the left front
wheel and the right front wheel rotate at different rates, which
may cause a torque that turns a patient side cart at the desired
yaw rate. By configuring a drive system of a patient side cart to
turn the cart by turning driven wheels at different speeds, the
cart may be advantageously permitted to pivot about a point located
between the driven wheels. This may provide smoother, tighter
turning in comparison to a cart that pivots about a point located
outside (not between) the driven wheels of the cart.
To provide feedback control, output signals may be provided from
cart dynamics section 780 and fed back within the control system
700. For instance, cart dynamics section 780 may provide a fore/aft
output signal 792 and a yaw rate output signal 794. As shown in
FIG. 8, fore/aft output signal 792 may be compared with the desired
fore/aft movement signal 712, such as at error detector 714, and
yaw rate output signal 794 may be compared with the desired yaw
rate signal 722, such as at error detector 724. Any differences
resulting from the comparison at error detectors 714, 724 are sent
to feedback control modules 750, 760, respectively. Fore/aft
feedback control module 750 may be configured to produce a fore/aft
feedback command output 752, which is combined with the fore/aft
command output 732, such as at adder 772, to provide a corrected
fore/aft command output 776, which is in turn sent to cart dynamics
section 780. Yaw feedback control module 760 may be configured to
produce a yaw rate feedback command output 762, which is combined
with the yaw rate command output 742, such as at adder 774, to
provide a corrected yaw rate command output 778, which is in turn
sent to cart dynamics section 780.
A patient side cart may include features or embodiments in addition
to those discussed above. For example, although it is desired that
a drive system of a patient side cart will provide motive force to
move the cart so that minimal effort will be required from a user,
it may be desirable for the drive system to not provide all of the
force necessary to move the cart in a desired manner. According to
an exemplary embodiment, the drive system of a patient side cart
may provide the majority of the force necessary to move the cart
but require a user to provide a small degree of the force. In this
way, the user may feel the mass and handling of the cart when
pushing or pulling the cart. Thus, the user may understand how
massive the cart may be and how smoothly the cart moves so the user
may appreciate the care that should be used when moving the cart.
According to an embodiment, a control system of a patient side cart
may include one or more filters to affect the command outputs
issued to the driven wheels of the cart, such as by reducing the
amount of torque applied to the wheels or by reducing a desired
velocity or acceleration for the driven wheels.
According to an exemplary embodiment, a patient side cart may
include one or more safety devices to cut power for the drive
system when a patient side cart is not being moved. For example, a
steering interface may include one or more "dead man" switches, as
discussed in U.S. application Ser. No. 14/208,663, filed on Mar.
13, 2014 and claiming priority to U.S. Provisional Application No.
61/791,924 entitled "Surgical Patient Side Cart with Steering
Interface" and filed on Mar. 15, 2013, each of which is
incorporated by reference herein in its entirety. Thus, when a user
is not applying a sufficient force to a steering interface, the
steering interface may stop providing a signal from the "dead man"
switch. When such a signal is no longer received by the drive
system of a patient side cart, the drive system may be configured
to cease power to driven wheels to stop movement of the cart. In
addition, a patient side cart may include a manual brake control or
an emergency kill switch for a user to cut power to the cart.
When the "dead man" switch is released, the drive system of a cart
may be configured to bring the cart to an immediate stop, according
to an exemplary embodiment. For instance, the drive system may
apply brakes to bring the cart to an immediate stop. According to
an exemplary embodiment, a brake mechanism may be configured to
brake a driven wheel of a cart, such as, for example, one or both
of front wheels 410, 412 of the exemplary embodiment of FIG. 3.
However, the exemplary embodiments described herein are not limited
to braking only driven wheels of a cart. According to an exemplary
embodiment, a brake mechanism may be configured to brake a
non-driven wheel of a cart, such as, for example, one or both of
non-driven rear wheels 420 of the exemplary embodiment of FIG. 3.
According to another exemplary embodiment, both driven wheels and
non-driven wheels may be braked.
In one exemplary embodiment, braking can be accomplished by a brake
mechanism alone without any use of motors to decelerate a cart,
such as the motors 411, 413 of the exemplary embodiment of FIG. 3.
According to another exemplary embodiment, a cart may be gradually
decelerated once a "dead man" switch has been released to bring the
cart to a smoother stop, in comparison to when braking is
immediately applied upon release of the "dead man" switch. For
instance, one or more motors may be used to gradually decelerate a
cart over a period of time, such as by applying a negative torque
to wheels connected to the motors. In another exemplary embodiment,
if the drive wheels are pivotable, directions of the drive wheels
could be changed in a pair-wise manner so that the drive wheels
oppose each other, thus increasing friction to achieve
deceleration. The period of deceleration may depend, for example,
upon the speed of the cart at the time the "dead man" switch is
released. In various exemplary embodiments, the period of
deceleration may increase as the speed of the cart increases. The
cart speed used to determine the period of deceleration may be, for
example, an actual cart speed or a target cart speed at the time
the "dead man" is released. Once the period of deceleration has
passed, brakes may be applied to bring the cart to a stop.
In another exemplary embodiment, the brakes of a cart may be
configured to apply a variable braking force. For example, the
brakes can apply a first, lower level of braking force during the
period of deceleration and then apply a second, higher level of
braking force to bring the cart to a stop once the period of
deceleration has ended.
According to an exemplary embodiment, the "dead man" switch may be
used to overcome a fault status for a patient side cart to permit
the cart to be moved. A fault may occur, for example, when a
problem occurs with a drive motor, which may cause the brakes of
the cart to be automatically engaged to minimize or prevent further
movement of the cart while the cart has a fault status. The "dead
man" switch may be depressed by a user to disengage the brakes to
place the cart in a neutral, "free-wheeling" state that permits a
user to push the cart to a different location, even when the cart
has a fault status. According to an exemplary embodiment, when the
cart is in a neutral, free-wheeling state, motor windings may be
opened to prevent electromechanical braking, which may otherwise
result if the windings were closed. According to an exemplary
embodiment, if the "dead man" switch is released before the fault
condition is cleared, the brakes of the cart are reengaged. If the
"dead man" switch is depressed by a user at the same time when a
fault condition occurs, the controls may be configured to sense
release of the "dead man" switch followed by re-depression of the
switch to cause disengagement of the brakes.
A "dead man" switch may have various levels of sensitivity
corresponding to differing actions performed by a patient side
cart, according to an exemplary embodiment. For instance, when the
"dead man" switch is not depressed, power is not supplied to the
drive system of the cart. When the "dead man" switch is depressed
by application of a first amount of force, the cart functions
normally and the brakes of the cart are not engaged. When the "dead
man" switch is depressed by application of a second amount of force
greater than the first amount of force, the cart may be
deactivated, such as by cutting power to the drive system of the
cart. According to an exemplary embodiment, the second amount of
force may correspond to a situation in which a user firmly grasps a
handle of the cart when the user is alarmed, such as due to a
flight or fight response. Because the user is alarmed and reacts by
grasping the handle even more firmly, rather than releasing the
handle, the cart would not otherwise be deactivated (such as when
the "dead man" switch is released). Thus, making the "dead man"
switch sensitive to the second, higher amount of pressure permits
the drive system of a cart to be disengaged when a user presses the
"dead man" switch with the second, higher amount of force, such as
when the user is alarmed and grasps a handle of the cart more
firmly.
According to an exemplary embodiment, the drive system of a patient
side cart may include traction control. During movement of a
patient side cart, one or more wheels of the cart may lose traction
with a ground surface, such as when the ground surface is slippery
or when inertial loads during movement of the cart or when
traversing hills of various slopes in various directions, resulting
in a transfer of weight from one wheel to another. When the drive
system of a cart includes traction control, the cart may respond to
traction loss by changing commands to drive motors for wheels so
that motion of cart corresponds to a motion desired by a user to a
greater degree, in comparison to when the cart is experiencing a
loss of traction. For instance, when a particular wheel loses
traction, the speed of the contact surface for that particular
wheel relative to the ground may become non-zero. According to an
exemplary embodiment, a drive system of a cart may respond to a
loss of traction for a particular wheel by reducing the driving or
braking torque applied to that particular wheel. Turning to FIG. 9,
a top schematic view of an exemplary embodiment of a wheel
arrangement for a patient side cart 800 is shown, includes driven
front wheels 810, 812 and rear wheels 820, 822. In the exemplary
embodiment of FIG. 9, driven front wheel 810 has encountered a low
friction region 830 of a ground surface, resulting in a loss of
traction for front wheel 810. In response to the loss of traction
for front wheel 810, a drive system of a cart may reduce the
magnitude of the torque for front wheel 810 to reduce slip between
front wheel 810 and the ground surface. The direction of the torque
for front wheel 810 may be either positive (e.g., for acceleration)
or negative (e.g., for deceleration). According to an exemplary
embodiment, the torque for driven front wheel 812 may also be
adjusted, which may result in a reduction in the control of cart
800 in a fore/aft direction 840 but enhancement of the control of
cart 800 in a yaw direction 842. In other words, control of cart
800 in fore/aft direction 840 may be sacrificed via traction
control so that cart 800 may be controlled in yaw direction 842.
For instance, if only wheels 810, 812 are driven and wheel 810
loses traction, virtually only one degree of freedom may remain for
controlling the motion of cart 800 via driven wheel 812. Thus, a
drive system for cart 800 may be configured to control the motion
of cart 800 in yaw direction 842, such as by adjusting the torque
for wheel 812, instead of controlling the motion of cart in
fore/aft direction 840 while wheel 810 lacks traction.
According to an exemplary embodiment, a drive system of a patient
side cart (such as the drive system 500 of the exemplary embodiment
of FIG. 5 and a drive system including the control systems of the
exemplary embodiments of FIGS. 6-8) may include one or more devices
to determine when a loss of traction occurs. For instance, traction
loss may be detected by a sensor, such as, for example, a yaw rate
sensor. According to another exemplary embodiment, traction loss
may be determined by a model of the dynamics of a patient side cart
and a model of the dynamics of the stand-alone wheel. For instance,
one model may provide the behavior of the cart when a loss of
traction occurs between one or more wheels, such as one or more
driven wheels, and a ground surface and another model may provide
the behavior of the cart when no slip occurs, which may also be
used to correct the behavior of the cart when there is a loss of
traction. According to an exemplary embodiment, when a drive system
of a cart uses speed control (e.g., commands the cart to move at a
certain speed), the drive system could analyze the input for a
particular wheel to determine if the drive command is below a
predetermined threshold indicating a loss of traction. The input to
be analyzed may be, for example, the inertia, torque, and/or power
of the wheel. When speed control is used for a cart and a wheel of
the cart loses traction, the input for that wheel likely decreases
as the drive system maintains a desired speed of the cart. Thus,
the drive system may analyze inputs for the various wheels of a
cart to determine whether the input has diminished below a
predetermined threshold. According to another exemplary embodiment,
a drive system may analyze an input to determine if the input is
below a predetermined threshold for a predetermined amount of time
to determine when a loss of traction is occurring.
According to an exemplary embodiment, a drive system may determine
the inertia of a wheel to determine whether a loss of traction is
occurring. For instance, by knowing a wheel torque and an
acceleration of a wheel, one may determine the inertia of a wheel.
When a wheel of a cart has lost traction with a ground surface, the
inertia of the wheel is relatively low because the inertia is
substantially that of just the wheel. Conversely, the inertia is
higher when the wheel has traction with the ground surface because
the measured inertia is not only that of the wheel but also at a
least a portion of the cart. A drive system of a cart may determine
whether the inertia is lower than a predetermined inertia
threshold. When the inertia is lower than the threshold, the drive
system determines that the wheel has lost traction and enacts yaw
control. According to an exemplary embodiment, the drive system may
repeat its determination of wheel inertia and compare the inertia
to the threshold, continuing to enact yaw control until the drive
system determines that the inertia is greater than the threshold,
which indicates that traction has been restored.
According to an exemplary embodiment, instead of using a
predetermined inertia threshold and enacting traction control if a
wheel inertia falls below the threshold, a drive system may
implement a continuum for motion control. For instance, once
inertia has been determined for a wheel, a drive system may
determine where the determined wheel inertia falls on a continuum
ranging from a small inertia, which may correspond to a wheel that
lacks traction, to a large inertia, which may correspond to a cart
wheel having traction. The drive system may then use a control
value corresponding to where the wheel inertia falls on the
spectrum when using traction control. Thus, the traction control
utilizing a continuum may be sensitive to the amount of slipping
and control movement according to the amount of slipping.
According to another embodiment, a patient side cart may include a
kick plate. As shown in the exemplary embodiment of FIG. 2, a kick
plate 320 having a sensor may be located at the rear of a patient
side cart, e.g., the side of the cart where the steering interface
is located. A steering interface 300 may be designed according to a
situation when a user is pushing off of a ground surface to apply a
force to the steering interface 300. However, if a user puts a foot
on the back of a patient side cart in an attempt to help move the
cart forward, while simultaneously holding the steering interface
300, there may be a tendency to pull back on the steering interface
in the X (aft) direction. In this situation, since the force
applied to the steering interface 300 is in the X (aft) direction,
the cart would move backward in the aft direction toward the user,
even though the user is attempting to move the cart forward by
using the user's foot. To prevent this situation, the kick plate
320 can be configured to send a signal to stop power to drive the
cart when a user engages or strikes the kick plate 320. For a
further explanation regarding an embodiment of a kick plate that
can be used, reference is made to U.S. application Ser. No.
14/208,663, filed on Mar. 13, 2014 and claiming priority to U.S.
Provisional Application No. 61/791,924 entitled "Surgical Patient
Side Cart with Steering Interface" and filed on Mar. 15, 2013.
According to an exemplary embodiment, a patient side cart may
include a system to prevent or minimize collisions between the cart
and other objects. For example, a patient side cart may include
radar or a light detection and ranging (LIDAR) system that detects
objects in the path of the cart and issues a signal to the control
system of the cart warning of a possible collision, which may cause
the cart to stop.
According to an exemplary embodiment, the drive system also may be
configured to adjust the wheels of a patient side cart to permit
the cart to move in sideways manner. For instance, driven wheels
410, 412 in FIG. 3 may be rotated left or right ninety degrees
(e.g., from their position shown in FIG. 3) and locked into that
orientation so that cart 400 may be permitted to move only sideways
along the Y direction. According to an exemplary embodiment, such a
rotation of wheels may be actuated by a control located on the
steering interface of a patient side cart. Because wheels 420, 422
may be free to rotate, wheels 420, 422 will follow the movement of
wheels 410, 412. Such a configuration may permit a patient side
cart to enter relatively tight spots and move in a manner that
would be otherwise difficult by turning cart via driven wheels 410,
412 as discussed above. In this mode of transportation, force on
the steering interface 400 in the Y direction will cause sideways
movement either to the left or the right depending on the direction
the force is exerted on the steering interface 400 in the Y
direction.
By providing a patient side cart with a drive system, the
relatively large weight of the cart may be moved without requiring
the user to provide the force necessary to move the patient side
cart without the drive system. Further, the drive system may
include a relatively accurate and stable control system that uses
modeled behavior of the cart and feedback control.
Exemplary embodiments, including the various operational methods
described herein, can be implemented in computing hardware
(computing apparatus) and/or software, such as (in a non-limiting
example) any computer that can store, retrieve, process and/or
output data and/or communicate with other computers. The results
produced can be displayed on a display of the computing hardware.
One or more programs/software comprising algorithms to affect the
various responses and signal processing in accordance with various
exemplary embodiments of the present disclosure can be implemented
by a processor, such as data interface module, of or in conjunction
with the control cart including core processor and may be recorded
on computer-readable media including computer-readable recording
and/or storage media. Examples of the computer-readable recording
media include a magnetic recording apparatus, an optical disk, a
magneto-optical disk, and/or a semiconductor memory (for example,
RAM, ROM, etc.). Examples of the magnetic recording apparatus
include a hard disk device (HDD), a flexible disk (FD), and a
magnetic tape (MT). Examples of the optical disk include a DVD
(Digital Versatile Disc), a DVD-RAM, a CD-ROM (Compact Disc-Read
Only Memory), and a CD-R (Recordable)/RW.
Further modifications and alternative embodiments will be apparent
to those of ordinary skill in the art in view of the disclosure
herein. For example, the systems and the methods may include
additional components or steps that were omitted from the diagrams
and description for clarity of operation. Accordingly, this
description is to be construed as illustrative only and is for the
purpose of teaching those skilled in the art the general manner of
carrying out the present teachings. It is to be understood that the
various embodiments shown and described herein are to be taken as
exemplary. Elements and materials, and arrangements of those
elements and materials, may be substituted for those illustrated
and described herein, parts and processes may be reversed, and
certain features of the present teachings may be utilized
independently, all as would be apparent to one skilled in the art
after having the benefit of the description herein. Changes may be
made in the elements described herein without departing from the
spirit and scope of the present teachings and following claims.
It is to be understood that the particular examples and embodiments
set forth herein are non-limiting, and modifications to structure,
dimensions, materials, and methodologies may be made without
departing from the scope of the present teachings.
Other embodiments in accordance with the present disclosure will be
apparent to those skilled in the art from consideration of the
specification and practice of the invention disclosed herein. It is
intended that the specification and examples be considered as
exemplary only, with a true scope and spirit being indicated by the
following claims.
* * * * *